1. Field of the Invention
The present disclosure relates to a method of compressed sensing in ultra wide band systems with narrow band interference.
2. Description of Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Ultra Wide-Band (UWB) technology is a promising a cutting edge technology in delivering high data rate for short range wireless communication systems. It is suitable for applications which need low power such as multi-hop wireless networks. Recently, UWB technology became a good candidate for short-range indoor high-resolution positioning systems. UWB signals have the ability to trade bandwidth for a reduced transmission power. This can be achieved by sending a very short pulse duration which means very large bandwidth. UWB signals include not only carrier-less base-band signals, such as Impulse Radio (IR) or non-sinusoidal pulses, but also wide-bandwidth signals with carriers, such as Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM).
UWB radios are expected to be the next generation of transmission system that can support high data rate and power-constrained applications such as wireless sensor and body area networks. Because of their large bandwidth, two problems arise, namely the high speed analog-to-digital-conversion (ADC) required at the receiver side and the coexistence with other narrowband systems that share the same part of the spectrum. The two problems can be reduced using compressive sensing (CS). Narrowband interference (NBI) sources can be licensed or unlicensed signals with different center frequencies and different bandwidths.
Because of their large bandwidth, UWB signals may encounter some problems especially with high sampling rate required at the receiver side. Reducing the complexity of UWB receiver is an important issue. Moreover, coherence existence with other narrowband systems is a major concern which needs to be addressed through a proper mechanism. CS is a promising signal processing solution which can reduce the sampling requirements as well as avoid the interference with narrowband systems.
Narrowband Interference (NBI) signals may have two scenarios. One of them is overlaying the UWB spectrum over a licensed narrowband signal. The other is the intentional jamming where someone share part of the UWB spectrum in order to disturb the existence transmission. See T. H. Stitz, T. Ihalainen, M. Renfors, “Mitigation of Narrowband Interference in Filter Bank Based Multicarrier Systems,” in IEEE Communications Society, Vol. 7, pp. 3241-3246, 2006, incorporated herein by reference in its entirety. Because of the power constraint of UWB signals, the mitigation of the NBI over UWB system is a challenging task. Although, both narrowband and UWB systems may affect each other, the interest is on mitigation of the NBI effect on UWB systems. When the narrowband signals are very strong, they will interfere with UWB signal and may degrade the system performance. See F. Dowla F. Nekoogar, and A. Spiridon, “Interference Mitigation in Transmitted-Reference Ultra-Wideband Receivers,” in IEEE Antennas and Propagation Society, Vol. 4, pp. 1307-1310, June, 2004; H. Nikookar and R. Prasad, Introduction to Ultra Wideband for Wireless Communications, Springer, 2009; and C. Wang, M. Ma, R. Ying, and Y. Yang, “Narrowband Interference Mitigation in DSUWB Systems,” in IEEE Signal Processing, Vol. 17 pp. 429-432, 2010, each incorporated herein by reference in their entirety.